linux-kernel - [GIT PULL] KVM: Dirty Ring changes for 6.17

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Message-ID: <20250725220713.264711-3-seanjc@google.com>
Date: Fri, 25 Jul 2025 15:07:02 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Sean Christopherson <seanjc@...gle.com>
Subject: [GIT PULL] KVM: Dirty Ring changes for 6.17

A set of Dirty Ring changes to fix a flaw where a misbehaving userspace can
induce a soft lockup, along with general hardening and cleanups.

The following changes since commit 28224ef02b56fceee2c161fe2a49a0bb197e44f5:

  KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities (2025-06-20 14:20:20 -0400)

are available in the Git repository at:

  https://github.com/kvm-x86/linux.git tags/kvm-x86-dirty_ring-6.17

for you to fetch changes up to 614fb9d1479b1d90721ca70da8b7c55f69fe9ad2:

  KVM: Assert that slots_lock is held when resetting per-vCPU dirty rings (2025-06-20 13:41:04 -0700)

----------------------------------------------------------------
KVM Dirty Ring changes for 6.17

Fix issues with dirty ring harvesting where KVM doesn't bound the processing
of entries in any way, which allows userspace to keep KVM in a tight loop
indefinitely.  Clean up code and comments along the way.

----------------------------------------------------------------
Sean Christopherson (6):
      KVM: Bound the number of dirty ring entries in a single reset at INT_MAX
      KVM: Bail from the dirty ring reset flow if a signal is pending
      KVM: Conditionally reschedule when resetting the dirty ring
      KVM: Check for empty mask of harvested dirty ring entries in caller
      KVM: Use mask of harvested dirty ring entries to coalesce dirty ring resets
      KVM: Assert that slots_lock is held when resetting per-vCPU dirty rings

 include/linux/kvm_dirty_ring.h |  18 ++-----
 virt/kvm/dirty_ring.c          | 111 +++++++++++++++++++++++++++++------------
 virt/kvm/kvm_main.c            |   9 ++--
 3 files changed, 89 insertions(+), 49 deletions(-)